The Advanced Telecommunications Architecture (ATCA) (also referred to as Advanced TCA) standard defines an open switch fabric based platform delivering an industry standard high performance, fault tolerant, and scalable solution for next generation telecommunications and data center equipment. The development of the ATCA standard is being carried out within the PCI Industrial Computer Manufacturers Group (PICMG).
The Advanced TCA 3.0 base specification defines the physical and electrical characteristics of an off-the-shelf, modular chassis based on switch fabric connections between hot-swappable blades. This specification defines the frame (rack) and shelf (chassis) form factors, core backplane fabric connectivity, power, cooling, management interfaces, and the electromechanical specification of the ATCA-compliant boards. The electromechanical specification is based on the existing IEC60297 EuroCard form factor, and enables equipment from different vendors to be incorporated in a modular fashion and be guaranteed to operate. The ATCA 3.0 base specification also defines a power budget of 200 Watts (W) per board, enabling high performance servers with multi-processor architectures and multi gigabytes of on-board memory.
Although the ATCA standard is a step in the right direction with respect to providing standardized telecom and computer component interfaces and interoperability, several of its design aspects are limiting. Notably, the 200 W power dissipation per board slot places a restriction on how much heat can be generated by a board, while not defining the location of the heat sources. (It is noted the 200 W limit applies to boards occupying a single slot. Higher power dissipations are allowed for boards occupying multiple slots, e.g., a front board occupying two slots is limited to 400 W). In order to meet ever increasing bandwidth demand, equipment capabilities need to increase, requiring faster processors, among other board component improvements. When considering identical semiconductor fabrication processes, there is a direct relationship between speed and power consumption—the faster the processor speed, the greater the power consumption of the processor, and thus the greater the amount of heat that must be dissipated by an ATCA board hosting the processor. In view of the rigid board and shelf form factors defined by the ATCA base specification, this leads to problems in achieving sufficient cooling for high-power components such as processors, since the majority of the 200 W will be consumed by such components.